Berlin 2012 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 26: Poster Session: Heterostructures - Preparation and Characterization - Impurities / Amorphous Semiconductors
HL 26.14: Poster
Montag, 26. März 2012, 16:00–19:00, Poster D
Hall Mobility Measurements on Amorphous Phase-Change Materials — •Matthias Kaes, Hanno Volker, and Matthias Wuttig — I. Physikalisches Institut (IA), RWTH Aachen, 52056 Aachen
Phase-change materials (PCMs) exhibit a rapid crystallization of their amorphous phase and a related change in electrical conductivity of several orders of magnitude. Studies of the electronic structure in the crystalline phase have revealed a surprising tendency of quasibinary PCM alloys (GeTe)x(Sb2Te3)1−x to display a disorder-induced metal-insulator transition ([1]). In contrast, the study of electronical properties of amorphous-phase change materials has, so far, been confined to the study of DC-conductivity and photoconductivity, which have revealed p-type conduction as well as the presence of deep defects and shallow defects in the mobility gap ([2]).
Here, we present Hall measurements on amorphous quasibinary PCM-alloys employing an AC-Hall technique. Modulating not only the external magnetic field but also the voltage applied on the sample, an excellent signal to noise ratio can be achieved. The extracted Hall mobilities are anomalously signed and in the range of 0.1 cm2/Vs at 300 K. In addition, the Hall mobility increases with temperature and displays stoichiometric trends. The results are discussed in light of two-channel and small-polaron transport models.
[1] T. Siegrist et al., Nature Materials 10, p. 202-8 (2011).
[2] J. Luckas et al., Journal of Applied Physics 110, p. 013719 (2011).